Capsules and process for forming capsules

ABSTRACT

Capsules having an improved vapor barrier together with improved shell thickness, uniformity and strength comprise a central core of liquid fill material surrounded and enclosed by an outer shell, said shell containing at least one soluble surfactant in particular, sodium dioctylsulfosuccinate, sodium carboxymethyl cellulose, sorbitan sesquioleate, silicones, interpolymer of methyl vinyl ether and maleic anhydride, mixtures thereof, or fluorocarbon compounds.

ite Statfi Belles CAPSULES AND PROCESS FOR FORMING CAPSULES [75]inventor: Theodore F. Belles, Woodbury,

Minn.

[73] Assignee: Minnesota Mining and Manufacturing Company, St. Paul,Minn.

[22] Filed: Dec. 4, 1970 [21] Appl. No.: 95,036

[52] US. C1.....; 252/316, 8/79, 99/140 R, 99/166, 117/100 A, 117/100 B,252/10,

[51] Int. Cl BOlj 13/02, B29c 13/00, 844d H02 [58] Field of Search252/316; 117/100 A, 117/100 B; 264/4; 424/38, 35

[ Dec. 18, 1973 3,154,494 10/1964 Speak ct ul. 252/96 3,423,489 H1969Arens ct a1. 264/4 3,069,370 12/1962 Jensen et al. 252/316 X PrimaryExaminerRichard D. Lovering Attorney-Kinney, Alexander, Sell, Steldt &Delahunt [5 7] ABSTRACT Capsules having an improved vapor barriertogether with improved shell thickness, uniformity and strength comprisea central core of liquid fill material surrounded and enclosed by anouter shell, said shell containing at least one soluble surfactant inparticular, sodium dioctylsulfosuccinate, sodium carboxymethylcellulose, sorbitan sesquioleate, silicones, interpolymer of methylvinyl ether and maleic anhydride, mixtures thereof, or fluorocarboncompounds.

8 Claims, 1 Drawing Figure ORA E75 INVENTOR THEUOOFE 550MB WM MPAIENIEDBEc 18 M5 1 CAPSULES AND PROCESS FOR FORMING CAPSULES BACKGROUNDOF THE INVENTION The invention relates to improved capsules.

A wide variety of materials, including adhesives, dyes, cleaningsolutions, foods, lubricants, pesticides, etc., have been packaged inrelatively small capsules for release at a later time by rupture of thecapsule shell wall. Such capsules typically comprise a shell materialsurrounding and enclosing a central core of liquid material and aretypically ruptured by heat, pressure and- /or dissolution when releaseof the capsule contents is desired.

Several techniques of preparing these capsules are known, the mostcommon being formation of concentric tubes or biliquid columns of shellmaterial around liquid fill material and causing the column to break upand solidify in the form of spheroid capsules. US. Pat. No. 3,423,489discloses a particularly useful method of forming capsules, indicatingthat optimum results are obtained by including surfactant in the fillliquid. These capsules, while suitable for some commercial uses, oftenhave not had sufficient shell strength and uniformity. Also, the capsuleshells have not provided an adequate vapor-barrier to some liquids.Furthermore, it has not readily been possible to effectively encapsulatealcohol solutions in wax shells; nor organic solutions in shells such assugars, gelatin, water soluble material, or polymers such ashydroxypropyl cellulose, methyl cellulose and other natural andsynthetic gums.

SUMMARY OF THE INVENTION The invention provides capsules the shells ofwhich have improved strength and uniformity. Resistance of the shell topassage of fill vapors is increased. Practice of the invention makespossible encapsulation of alcohol solutions in wax shells, organicsolutions in shells such as sugars, gelatin, water soluble material, orpolymers such as hydroxypropyl cellulose, methyl cellulose and othernatural and synthetic gums.

ln accordance with the invention, the capsules comprise a central coreof liquid fill material surrounded and enclosed by an outer shell, saidshell containing at least one soluble surfactant.

BRIEF DESCRIPTION OF THE DRAWING The drawing graphically illustrates theimproved half-life (time for one-half of the fill to evaporate throughthe shell) obtained by incorporation of surfactant in the shell. Thelower line depicts the percent fill remaining at various time intervalsin a capsule shell without surfactant and corresponds to Example 1herein. The center line depicts the percent fill remaining at varioustime intervals in a capsule shell containing 0.1% fluorocarbonsurfactant and corresponds to Example 2 herein. The upper line depictsthe percent fill remaining at various time intervals in a capsule shellcontaining 0.1% sorbitan sesquioleate surfactant and 0.1% fluorocarbonsurfactant and corresponds to Example 6 herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The capsule shells may comprisesuch materials as hydrocarbon waxes, hydrocarbon polymers, gelatins,sugars, water soluble polymers such as hydroxypropyl cellulose, methylcellulose and other natural and synthetic gums, etc. Upon inclusion of aminor amount of at least one soluble surfactant in the shellcomposition, the shelf, storage, or half-life (time one-half of the fillto evaporate through the shell) of the capsules is considerablyincreased. Indeed, the time for one-half of the fill to evaporatethrough the shell is approximately doubled.

Surfactants found useful to provide the improved capsules of theinvention are those which l are soluble in the shell composition beingutilized, (2) lower the equilibrium surface tension between air andliquid shell composition by at least 2 dynes/cm, (3) improve the abilityof the shell composition to wet the fill, and (4) have a boiling pointgreater than the temperature reached by the shell composition duringencapsulation.

A surfactant is considered soluble in the shell composition if it ishomogeneously dispersible in liquid shell composition having a viscosityof about 2 to about 2,000 cps at a concentration of about 0.001 to 10%by weight. Surfactants found to improve ability of the shell compositionto wet the fill and provide improved capsules are those which whenhomogeneously dispersed in a drop of liquid shell composition at aboutlO200C above its melting or congealing point will cause the drop tospread rapidly on fill at room temperature and not subsequentlycontract. Surfactants which cause the drop of liquid shell compositionto rapidly spread and then slowly contract have a less than optimumeffectiveness. Surfactants which cause the drop of liquid shellcomposition to slowly spread, but not contract, have an effectivenessconsiderably less than optimum. Surfactants which cause the drop ofliquid shell composition to spread and rapidly contract or which do notcause spreading have not been found effective.

Typical surfactants found useful to provide the improved capsules of theinvention are fluorocarbon compounds such as wherein n represents aninteger from 2 to 8 inclusive; silicones such as siloxane-oxyalkylanecopolymers and dimethylsilicone polymers; and hydrocarbon surfactantssuch as sodiumdioctylsulfosuccinate, sodium carboxymethyl cellulose,sorbitan sesquioleate, polyoxyethylene polyol fatty acid esters, andinterpglymer s of methyl vinyl ether and maleic anhydride. Mixtures ofseveral compatible surfactants may also be used.

The improved capsules of the invention are prepared by mixing at leastone soluble surfactant with the liquid shell composition, thereafterproviding a biliquid column comprising an outer layer of liquid shellcomposition and a core of liquid fill, and thereafter causing the columnto break into droplets with the shell composition solidifying in theform of spheroid capsules, the fill being contained therein. Thispermits encapsulation of alcohols in wax shells, organic solutions inshells of sugars, gelatin, water soluble material, and polymers such ashydroxypropyl cellulose, methyl cellulose and other natural andsynthetic gums. Where it has been possible to make capsules,incorporation of a soluble surfactant in the shell composition typicallyincreases the yield of satisfactory capsules by about 50 to 100 percent,increases the shelf, storage, or half-life of the capsules by about 25to 100 percent, provides capsules having a more uniform sizedistribution, increases the rate at which capsules may be produced andprovides shells having improved strength and uniformity. The diameter ofthe capsules produced are on the order of to 4000 microns.

The improved capsules obtained by practice of the invention is quiteunexpected and contrary to the prior art since surfactants havepreviously been included in the fill to provide an optimum yield ofcapsules. Practice of the invention by utilizing surfactant in the shellcomposition unexpectedly provides outstanding results in capsule yield,shelf life, size uniformity, strength, and increased production rate.

Mixing of the surfactant with the shell composition is typicallyaccomplished by melting the shell composition and thereafter blending inthe desired amount of surfactant. The effective amount of surfactant toachieve the objects of the invention is dependent upon the particularsurfactant utilized. For example, an effective amount of fluorocarbonsurfactant has been found to be about 0.01 to about 1 part by weight per100 parts of capsule shell composition. An effective amount of siliconesurfactant has been found to be about 0.01 to about 5, preferably 0.1 toabout 1 part per 100 parts by weight of shell composition. An effectiveamount of hydrocarbon surfactant has been found to be about 0.01 toabout 5, preferably 0.1 to about 1 part by weight per 100 parts of shellcomposition.

The invention is further explained and amplified without limitation bythe following examples in which all parts are by weight unless otherwiseindicated.

EXAMPLES l 12 These examples illustrate the increased capsule yield andincreased half-life obtained by practice of the invention and furtherillustrate use of a variety of surfactants in a hydrocarbon wax shellcomposition.

Half-life of the filled capsules was determined by placing pre-weighedcapsules in an open container and periodically reweighing the capsulesto determine the amount of fill lost. After several weighings have beenmade, a graph is plotted and the time for one-half of the fill toevaporate determined. In general, practice of the invention increasescapsule half-life by about 25 to 100 percent.

A capsule shell forming apparatus as described in FIG. 1 of US. Pat. No.3,423,489 was utilized to prepare capsules. The fill comprised 69.98%isopropyl alcohol, 30.00% water, 0.02% carboxy vinyl polymer(commercially available from the B.F. Goodrich Company under the tradedesignation Carbopol 941), and one drop of 1N sodium hydroxide pergallon. The shell composition comprised 5.0% high molecular weightethylene-isobutyl acrylate copolymer (commercially available from theDow Chemical Company under the trade designation Zetafax 1370), 0.1%bullte 192 1.9 9911? aqtipzie (Commercially TABLE I Percent increasePercent Percent in percent Half-life increase Example Surfactant yieldyield (years) in half-life 1 (control) None 69 0.40 0.1% Fluorocarbon 8421.8 .60 0.1% Organo-Silicone 89 29 .54 35 0.1% Sorbitan Sesquioleate 393 34.8 .54 35 O. 1% Fluorocarhon 94 36.2 .55 37.4 0.1% Fluorocarbon 9334.8 .69 72.6 0.1% Sorbitan Sesquioleate a Polyoxyethylene 91 3 i .9 .5947.5 Polyol fatty ester 0.1% Fluorocarbon 83 20.3 .66 0.1%Organo-Silicone 0.1 Fluorocarboni... 90 30.4 .60 50 0.1% Organo-Silicone86 24.6 .35 12.5 0.1% Organo-Silicone 91 31.9 .46 15 0.1% Fluorocarbon93 34.8

0.1% Organo-Silicone 7 Mixture of C F, SO N(CHCH O),.H wherein n= 2-8.

Commercially available from the Union Carbide Corporation, SiliconesDivision, under the trade designation L-77.

Commercially available from the Atlas Chemical Company under the tradedesignation Arlacel C".

Commercially availableTFom the Atlas Chemical Company under the tradedesignation Arlatone T.

Commercially available from the Union Carbide Corporation, SiliconesDivision, under the trade designation L-76" Commercially available fromthe Union Carbide Corporation, Silicones Division, under the Madedesignation L-".

available from Eastman Chemical Products, ln c. under the tradedesignation Tenox BHT), 94.9-X% paraffin wax having a melting point ofabout 140F. and X% surfactant as shown in Table 1.

Apparatus operating conditions utilized were: shell compositiontemperature of 1 l 50C.; fill tempera ture of 23C.; and nozzle orificediameter of 0.61 mm. Fill volume of the resultant capsules was found tobe 69% and the rate of production was 11.4 pounds of capsules per hour.

Percent yield of good capsules, percent increase in percent yield,half-life in years, and percent increase in half-life were determinedfor each example, the results being shown in Table 1.

Percent yield was determined by weighing all capsules and chaffproduced, removing the fill from damaged or cracked capsules by solventextraction or evaporation, separating the empty capsules and chaff fromthe good capsules by floatation in a liquid of appropriate density.Percent yield equals weight of good capsules divided by the total weightof all capsules and chaff times 100.

EXAMPLE 13 This example illustrates use of microcrystalline wax as thecapsule shell.

The same fill as utilized in Examples 1-12 was encap sulated in a shellcomprising 94.8% microcrystalline wax having a melting point of about177F, 5.0% of the high molecular weight ethylene copolymer used inExample 1, 0.1% butylated hydroxytoluene antioxidant and 0.1% surfactantcomprising a mixture of wherein n=2-8.

Apparatus operating conditions utilized were: shell compositiontemperature of 170C; fill temperature of 23C; and nozzle orificediameter of 0.61 mm. Fill volume of the resultant capsules was found tobe 72%.

By using surfactant, the production rate increased from 17.8 to 21.0lbs/hour percent increase), percent yield increased from 80 to 81%, andhalf-life increased from 0.33 to 0.42 years.

EXAMPLE 14 This example illustrates use of a fluorocarbon surfactant andan ethanol-water fill.

The shell composition utilized in Example 1 was used to encapsulate afill comprising 56.98% distilled water, 43% ethanol, and 0.02% ofacarboxyvinyl polymer viscosity builder (commercially available from theB.F. Goodrich Company under the trade designation Carbopol 941 Theorifice tip size was 0.61 mm, the jet length 0.5 inches, and the shellcomposition temperature 160C. The fill was found to be 71% of the totalcapsule volume. Capsule yield was 62% and half-life was about 0.3 years.

This example was repeated with 0.1% surfactant in the shell composition,the surfactant comprising a mixture of wherein n=2-8. Experimentalconditions and the fill were maintained the same. Yield of satisfactorycapsules increased from 62% to about 91% (about 50% increase) and thehalf-life increased from about 0.3 years to 0.77 years, (increase ofabout 157%).

EXAMPLE 15 This example illustrates the effect of utilizing surfactantin a beeswax capsule composition.

The capsule forming equipment described in Example 1 was utilized toencapsulate 98.5% distilled water and 1.5% interpolymer of methyl vinylether and maleic anhydride (commercially available from the GeneralAniline and Film Company under the trade designation Gantrez AN'169").The shell comprised sunbleached white beeswax. Operating conditionswere: nozzle jet length 3 inches; shell composition temperature C; andorifice tip diameter 0.61 mm. The fill comprised 68% by volume of thetotal capsule and the yield of good capsules was 67%.

This example was repeated utilizing the same conditions and materials,but with 0.1% surfactant in the shell composition, said surfactantcomprising a mixture of C H n n z l 0)" wherein n=2-8. Percent yield78%, a significant increase over the 67% obtained without use ofsurfactant.

EXAMPLE 16 This example illustrates capsules formed using surfactant inthe shell material, the capsules not being formable without use ofsurfactant.

A chlorofluorocarbon wax (commercially available from the MinnesotaMining and Manufacturing Company under the trade designation KELF 200")was utilized as the shell composition in an attempt to encapsulate afill comprising 70% isopropyl alcohol and 30% water using the equipmentdescribed in Example 1. The shell composition temperature was C. and wasslowly increased during the course of the trial to 180C. with nosignificant effect on capsule quality. A very small number of capsuleswere formed, most of them comprising groups of capsules adhered to eachother. All of the capsules were cracked and/or contained holes in theshell and none were satisfactory for use.

0.5% by weight of the fluorocarbon surfactant utilized in Example 15 wasincorporated in the shell composition and capsules again producedutilizing a shell temperature of C. Excellent capsules were obtainedwith approximately 88% of the capsule volume being fill. The capsuleshell was strong and solid containing no pin holes or cracks.

This example illustrates use of silicone surfactant in a gelatin shellcomposition.

The equipment described in Example 1 was utilized in an attempt toencapsulate 90% light mineral oil and orange flavor concentrate(commercially available from the Fritzsche Bros. Company under the tradedesignation Orange Flavor No. 100766062) in a shell comprising 15.23%gelatin (commercially available from the P. Liener & Sons Company underthe trade designation C. L. -Ex- 1443), 84.00% distilled water, 0.73%ethanol, 0.01% thymol, 0.03% Atlas Red 2 food coloring. The filltemperature was maintained at *l0C., the shell temperature at 30C., andan orifice tip of 0.63 mm. used. The biliquid column of shellcomposition and fill failed to form droplets and did not providecapsules.

The preceding example was repeated with 0.01% of silicone surfactant(commercially available from the Union Carbide Corporation under thetrade designation L-77) in the shell composition. Excellent capsuleshaving uniformly thick shells were obtained in about 95% yield.

EXAMPLE 18 This example illustrates the use of organic surfactants inMethocel shells to encapsulate mineral oil.

The encapsulation equipment described in Example 1 was utilized in anattempt to encapsulate 100% light mineral oil within a shell comprisinga dispersion of hydroxy-propylmethyl cellulose (commercially availablefrom the Dow Chemical Company under the trade designation Methocel60HG4000") in distilled water at 90C. The fill temperature wasmaintained at 24C., the shell composition temperature at 90C., and anorifice tip size of 0.65 mm. was used. The biliquid column turned insideout and attempted to coat mineral oil on solid spheres of shellmaterial. Satisfactory capsules were not obtained.

The proceding experiment was repeated with 0.5% sodiumdioctylsulfosuccinate in the shell composition, excellent capsules beingformed in about 95% yield.

sition was maintained at 90C. during encapsulation. Excellent capsuleswere obtained. No capsules were obtained without use of a surfactant.

EXAMPLE 19 EXAMPLE 20 The encapsulation equipment described in Example 1was used to encapsulate a fill comprising 20% orange oil and 80% lightmineral oil in an aqueous dispersion of hydroxypropyl cellulose(commercially available from Hercules Incorporated under the tradedesignation Klucel G) containing 2.0% sodium dioctylsulfosuccinate asthe shell composition. The shell compo- EXAMPLE 21 The encapsulationequipment described in Example 1 was used to encapsulate the fill ofExample 20 in a shell composition comprising 68% mannitol, 30% refinedcane sugar, and 2% sodium alkyl aryl sulfonate (commercially availablefrom the Monsanto Company, Inorganic Chemical Division, under the tradedesignation Santomerse No. 3 Paste). Excellent capsules were obtained inyield. No capsules were obtained without use of a surfactant.

' What is claimed is:

1. Capsules consisting essentially of a central core of organic fillliquid surrounded and enclosed by an outer shell, said outer shellcomprising a solidified organic shell-forming material selected from thegroup consisting of bees wax, paraffin wax, microcrystalline wax,sugars, natural gums, synthetic organic polymers, and gelatin, and,homogeneously dispersed therein, a surface tension lowering amount, notexceeding 10% by weight, of a surfactant, said surfactant selected fromthe group consisting of sodium dioctylsulfosuccinate, sodiumcarboxymethyl cellulose, sorbitan sesquioleate, silicones, andinterpolymer of methyl vinyl ether and maleic anhydride, and mixturesthereof.

2. Capsules consisting essentially of a central core of organic fillliquid surrounded and enclosed by an outer shell, said outer shellcomprising at least one sugar, and, homogeneously dispersed therein, asurface tension lowering amount, not exceeding 10% by weight, of sodiumdioctylsulfosuccinate.

3. Capsules consisting essentially of a central core of organic fillliquid surrounded and enclosed by an outer shell, said outer shellcomprising gelatin, and, homogeneously dispersed therein, a surfacetension lowering amount, not exceeding 10% by weight, of anorganosilicone.

4. Capsules consisting essentially of a central core of organic fillliquid surrounded and enclosed by an outer shell, said outer shellcomprising a solidified organic shell-forming material selected from thegroup consisting of bees wax, paraffin wax, microcrystalline wax,sugars, natural gums, synthetic organic polymers, and gelatin, and,homogeneously dispersed therein, a surface tension lowering amount, notexceeding 10% by weight, of a surfactant having the formula wherein nrepresents an integer from 2 to 8 inclusive;

5. Capsules according to claim 4 wherein said outer shell comprisesparaffin wax.

6. A process of forming capsules comprising a central core of fillsurrounded by an outer shell, said process comprising: providing amixture by dissolving a surface tension-lowering amount of a surfactantin an organic shell-forming material which is in a liquid state, saidorganic shell-forming material being selected from the group consistingof bees wax, paraffin wax, microcrystalline wax, sugars, natural gums,synthetic organic polymers, and gelatin, said surfactant selected fromthe group consisting of sodium dioctylsulfosuccinate, sodiumcarboxymethyl cellulose, sorbitan sesquioleate, silicones, aninterpolymer of methyl vinyl ether and maleic anhydride, and mixturesthereof, providing a core stream of liquid fill material enclosed by anouter concentric substantially cylindrical stream of said mixture andthereafter causing said outer concentric stream to constrict intosubstantially spherical incipient shells enclosing portions of saidliquid fill material, whereby the said capsules are obtained uponsolidification of said incipient shells.

7. A process of forming capsules comprising a central core of fillsurrounded by an outer shell, said process comprising: providing amixture by dissolving a surface tension-lowering amount of a surfactantin an organic shell-forming material which is in a liquid state, saidorganic shell-forming material being selected from the group consistingof bees wax, paraffin wax, microcrystalline wax, sugars, natural gums,synthetic organic polymers, and gelatin, and said surfactant being anorgano-silicone; providing a core stream of liquid fill materialenclosed by an outer concentric substantially cylindrical stream of saidmixture and thereafter causing said outer concentric stream to constrictinto substantially spherical incipient shells enclosing portions of saidliquid fill material, whereby the said capsules are obtained uponsolidification of said incipient shells.

wherein n represents an integer from 2 to 8 inclusive.

providing a core stream of liquid fill material enclosed by an outerconcentric substantially cylindrical stream of said mixture andthereafter causing said outer concentric stream to constrict intosubstantially spherical incipient shells enclosing portions of saidliquid fill material, whereby the said capsules are obtained uponsolidification of said incipient shells.

Patent No. 3, 779 ,942

Inven r) Theodore F. Bolles It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

insert after "0 .l" and before- "Fluorocarbon"; and r line 6 4',footnote that portion of the formula 7 reading "C F should read C7FColumn 5, line 37, that portion of the formula reading "C H should readC F Column 6, line 2, that portion of the formula; reading "C H shouldread 08F and line 35 that portion of the formula "C H should read 0 FColumn 7, line 13 (at the beginning of the line), insert the number signbefore t w and line 41, change "proceding" to preceding Q Column 10, i23 (at-the end of the line) after" "inclusive" change the period, to 'asemi-colon Attest: v

,..V A CCOY M, GIBSON JR, C. MARSHALL Arresting Officer Commissioner ofgg uscoMM-oc mmm FORM Po-mso (in-s9) I Column '4, line 51- (Example 9) 9in the column headed "Surfactant" I Signed and sealed this 24th day ofSeptember'- v UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTIONPatent No. 3,779,9'42 Dated lgggugr J}. 1313 Inventor(s) Theodore F.Bolles It is certified that error appears in the above-identified patentI and that said Letters Patent are hereby corrected as shown below:

I Column l, line 51- (Example 9), in the column headed "Surfactant"insert after "0 .l" and before- "Fluorocarbon"; and r 7 line 6 4',footnote that portion of the formula I II i I v reading C F should readC F I v Column 5, line 37, that portion of the formula reading "C Hshould. read 0 F Column 6, 'line 2,;that portion of the formula. reading"C H should read 08F f and line 35', that portion of the formula n,

"C' H should read C F l Column :7, line 13' ("at the beginning of theline), insert the i v 9 number sign before the 2 and line &1, change"proceding" to preceding,

colu n 10; line 23 (at the end of the line-) after "inclusive" hange theperiod (a) to a s mi-(301011 I f Signed and sealed this "24th day ofSeptem t al-afv Attest; I v -iili i IBSQ J c. MARSHALL BANK] AttestingOfficer 1 ommissioner of B aftents

2. Capsules consisting essentially of a central core of organic fillliquid surrounded and enclosed by an outer shell, said outer shellcomprising at least one sugar, and, homogeneously dispersed therein, asurface tension lowering amount, not exceeding 10% by weight, of sodiumdioctylsulfosuccinate.
 3. Capsules consisting essentially of a centralcore of organic fill liquid surrounded and enclosed by an outer shell,said outer shell comprising gelatin, and, homogeneously dispersedtherein, a surface tension lowering amount, not exceeding 10% by weight,of an organo-silicone.
 4. Capsules consisting essentially of a centralcore of organic fill liquid surrounded and enclosed by an outer shell,said outer shell comprising a solidified organic shell-forming materialselected from the group consisting of bees wax, paraffin wax,microcrystalline wax, sugars, natural gums, synthetic organic polymers,and gelatin, and, homogeneously dispersed therein, a surface tensionlowering amount, not exceeding 10% by weight, of a surfactant having theformula
 5. Capsules according to claim 4 wherein said outer shellcomprises paraffin wax.
 6. A process of forming capsules comprising acentral core of fill surrounded by an outer shell, said processcomprising: providing a mixture by dissolving a surface tension-loweringamount of a surfactant in an organic shell-forming material which is ina liquid state, said organic shell-forming material being selected fromthe group consisting of bees wax, paraffin wax, microcrystalline wax,sugars, natural gums, synthetic organic polymers, and gelatin, saidsurfactant selected from the group consisting of sodiumdioctylsulfosuccinate, sodium carboxymethyl cellulose, sorbitansesquioleate, silicones, an interpolymer of methyl vinyl ether andmaleic anhydride, and mixtures thereof, providing a core stream ofliquid fill material enclosed by an outer concentric substantiallycylindrical stream of said mixture and thereafter causing said outerconcentric stream to constrict into substantially spherical incipientshells enclosing portions of said liquid fill material, whereby the saidcapsules are obtained upon solidification of said incipient shells.
 7. Aprocess of forming capsules comprising a central core of fill surroundedby an outer shell, said process comprising: providing a mixture bydissolving a surface tension-lowering amount of a surfactant in anorganic shell-forming material which is in a liquid state, said organicshell-forming material being selected from the group consisting of beeswax, paraffin wax, microcrystalline wax, sugars, natural gums, syntheticorganic polymers, and gelatin, and said surfactant being anorgano-siliconE; providing a core stream of liquid fill materialenclosed by an outer concentric substantially cylindrical stream of saidmixture and thereafter causing said outer concentric stream to constrictinto substantially spherical incipient shells enclosing portions of saidliquid fill material, whereby the said capsules are obtained uponsolidification of said incipient shells.
 8. A process of formingcapsules comprising a central core of fill surrounded by an outer shell,said process comprising: providing a mixture by dissolving a surfacetension-lowering amount of a surfactant in an organic shell-formingmaterial which is in a liquid state, said organic shell-forming materialbeing selected from the group consisting of beeswax, paraffin wax,microcrystalline wax, sugars, natural gums, synthetic organic polymers,and gelatin, said surfactant being a compound having the formula